Field of the Invention
The present invention relates to a method for configuring an interface unit of a computer system and a computer system.
Description of the Background Art
Many computer systems have interface units for data exchange between a main processor and peripheral devices. An interface unit of this kind can be designed, for example, as a plug-in I/O card. Many interface units are equipped with their own processors for preprocessing incoming and outgoing data, whereby some interface units make it possible to adapt the programming of the processor in the interface unit flexibly to the requirements of the program executed by the main processor.
For example, the company Digi International Inc. provides an interface unit, freely programmable by the user, under the product name RabbitCore RCM4100. Another known approach is to store a plurality of program functionalities for preprocessing incoming and outgoing data persistently in the interface unit. The publication U.S. Pat. No. 6,189,052 B2, for example, describes this type of approach.
If the computer system is provided to execute the program, being executed by the main processor, in hard real-time, then the processes running on the computer system, in particular, also the processes executed by the processor stored in the interface unit, must be completed with certainty within a predefined time period. For this reason, the processor in the interface unit should function efficiently; i.e., the largest possible portion of the processor commands performed by it should be linked expediently to the programmed preprocessing of incoming and outgoing data. Furthermore, the processor stored in the interface unit should operate as deterministically as possible, therefore have low jitter, so that it is possible to estimate the time needed for executing processes sufficiently well.